PDA

View Full Version : Ideas for 120deg CCPM Mixing


Hodgepodge
Aug 13, 2003, 12:44 PM
Here is my attempt to wirte out what is happening when the transmitter mixes the channels.

Channels

1(v) aileron
2(w) elevator
3(x) collective
4(y) rudder
5(z) throttle


120 Mixing
. a
. / 0 \
. b___c


a = (w+x)/2
b = (0.5(w-1.5)+0.866(v-1.5)+(x-1.5))+1.5
c = (0.5(w-1.5)-0.866(v-1.5)+(x-1.5))+1.5

For b and c I took the offset of each mixed channel and multiplied it to get a value proportional to the actions of a. The sum of the channel's offsets and the centered value (1.5ms with ppm) determine the final value fed to the servo.

A is a direct mix so it's only necessary to average the two channels.

Was that clear as mud? This will eventually be programed into a MCU mixer so i don't have to go out and buy a new heli radio.

Hodgepodge
Aug 13, 2003, 12:46 PM
opps it seems the software doesn't like repeated spaces, you get the point with the "pseudo swash"